Metal fusion bonding – With means to juxtapose and bond plural workpieces – Strip leading end to trailing end bonder
Reexamination Certificate
2001-01-16
2002-11-12
Dunn, Tom (Department: 1725)
Metal fusion bonding
With means to juxtapose and bond plural workpieces
Strip leading end to trailing end bonder
C228S004500, C228S180500
Reexamination Certificate
active
06478212
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to wirebonding and, more particularly, to an apparatus and method for reduced downward force wirebonding of integrated circuits.
Recent advances in integrated circuit technology have brought about the incorporation of low dielectric constant (low-k) dielectrics into the devices. However, these copper/low-k materials are particularly susceptible to oxidation as the result of passivation damage, which is associated with activities such as handling, probing, and wirebonding. Wirebonding is the most common technology used in the electronic packaging industry for making electrical connections between the electrode pads on an integrated circuit chip and wires extending to a substrate providing external connections to the chip. Two examples of known wirebonding methods are “ball bonding” and “wedge bonding”.
Ball bonding is a process by which a wire is fed through and protrudes from a capillary hole in a bonding head. An electric arc melts the protruding wire into a ball which then solidifies. The solidified ball is pressed and flattened onto a bond pad by a bonding head. The ball/bond pad surface interface is then subjected to ultrasonic vibrations to form an electrical bond therebetween. In wedge bonding, a wedge feeds a wire through a clamp. Ultrasonic energy may then be used to bond the wire to a contact surface to form a first bond. The wedge is raised, forming a wire loop, and moves to a second bond site where a second bond is formed. The clamp thereafter pivots away from the tool to break the wire at the second bond.
Both ball bonding and wedge bonding are techniques which involve the application of a downward or normal force directly on the bond surface in order to successfully achieve an electrically sound bond between the wire and the bond surface. However, the downward force applied to the bond surface can cause damage to a passivation layer, frequently resulting in the oxidation of underlying metal therein. It is desirable, therefore to provide a method and/or apparatus which operates to reduce the amount of downward force applied to a bond surface.
SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a bond pad structure for an integrated circuit has a bondable base member for receiving a wire bonded thereon. A cavity is formed within the base member, with the cavity being configured to capture the wire therein. The cavity has a first open end having a first width and a second open end having a second width, with the first width being greater than second width. In a preferred embodiment, the cavity is tapered from one end to the opposite end, and is trapezoidally shaped. The base member is preferably comprised of an electrically conducting material, such as aluminum.
REFERENCES:
patent: 3648014 (1972-03-01), Bennett
patent: 4860941 (1989-08-01), Otto
patent: 4893742 (1990-01-01), Bullock
patent: 5269452 (1993-12-01), Sterczyk
patent: 5396104 (1995-03-01), Kimura
patent: 5598096 (1997-01-01), Pham et al.
patent: 5601740 (1997-02-01), Eldridge et al.
patent: 5626276 (1997-05-01), Lo et al.
patent: 5632438 (1997-05-01), Hoffmeyer et al.
patent: 5698903 (1997-12-01), Parris et al.
patent: 5775567 (1998-07-01), Lo et al.
patent: 5796549 (1998-08-01), Sedbrook et al.
patent: 5905308 (1999-05-01), Efland et al.
patent: 5920081 (1999-07-01), Chen et al.
patent: 5923088 (1999-07-01), Shiue et al.
patent: 5986343 (1999-11-01), Chittipeddi et al.
patent: 6031293 (2000-02-01), Hsuan et al.
patent: 6079610 (2000-06-01), Maeda et al.
patent: 6085962 (2000-07-01), Jacobson et al.
patent: 6105846 (2000-08-01), Evers et al.
patent: 6126062 (2000-10-01), Evers et al.
patent: 6138891 (2000-10-01), Evers et al.
patent: 6139977 (2000-10-01), Abys et al.
patent: 6242813 (2001-06-01), Huang et al.
Engel Brett H.
McGahay Vincent James
Nye, III Henry Atkinson
Dunn Tom
International Business Machines - Corporation
Pittman Zidia
LandOfFree
Bond pad structure and method for reduced downward force... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bond pad structure and method for reduced downward force..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bond pad structure and method for reduced downward force... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2939767